It is a gargantuan drill that has been hollowing out tunnels for a train station under Grand Central Terminal. As tall as four men and with the weight of two whales, the so-called cutter head -- the spinning, sharp-edged business end of a tunnel boring machine -- is usually extracted, dismantled and sold for scrap when the work is done.

But the Spanish contractor overseeing the project is taking a different approach. It believes it can save time and money by simply leaving it behind, dormant and decayed, within the rocky depths of Midtown Manhattan. The drill's final resting place: 14 stories beneath the well-tended sidewalks of Park Avenue.

There is little precedent for such a Brobdingnagian burial. No one at the Metropolitan Transportation Authority, which plans to officially entomb the machine sometime this week, can recall such an interment. "It's like a Jules Verne story," Michael Horodniceanu, the authority's chief of construction, said.

A recent visit to the cutter's future crypt revealed a machine that evokes an alien life form that crashed to earth a millennia ago. Its steel gears, bolts and pistons, already oxidizing, appeared lifeless and fatigued. A wormlike fan, its exhaust pipe disappearing into the cutter's maw, was still spinning, its drone not unlike a slumbering creature's breath.

In an official ceremony this week, the cutter will be sealed off by a concrete wall; the chamber will then be filled with concrete, encasing the cutter in a solid cast, Han Solo-style, so that it can serve as a support structure for the tunnel. A plaque will commemorate the site.